Russian forces lost nearly 300 sq km of net territory from March through September, ISW says
The Institute for the Study of War (ISW) reports that from March through September 2026 Russian forces lost net control of nearly 300 square kilometers of territory. In September alone the net Russian loss was about 80.81 square kilometers, with Russian troops also suffering more than 46,000 killed and wounded — the highest monthly figure for Russia in 2026. The Ukrainian 'Vivaldi' counter-offensive near Lyman accounts for much of September's territory change.
Key points
- ISW: Russian forces lost nearly 300 sq km of net territory from March through September 2026.
- In September 2026, Russia captured 175.54 sq km but lost 256.35 sq km — a net loss of 80.81 sq km (about minus 2.69 sq km per day).
- Russia's personnel losses in September exceeded 46,000 killed and wounded, the highest monthly figure of 2026.
- Russian territorial gains slowed significantly from March 2026 and have remained low or negative since.
- The September figures include at least about 150 sq km liberated by Ukraine in the Lyman area as part of the 'Vivaldi' operation.
- ISW says the Vivaldi counter-offensive near Lyman disrupted Russian attempts to encircle Ukraine's 'fortress belt.'
- Commander Andriy Biletsky said the Defense Forces have liberated 176 sq km since Vivaldi began; on September 15 he first publicly confirmed the operation.
Why it matters
ISW's assessment marks a shift in the territorial dynamics of the war: Russia's net monthly gains have been negative since March 2026, and September combined the largest personnel toll on Russia this year with no net territorial progress. The Lyman counter-offensive, named 'Vivaldi,' is identified as both an operationally significant success — disrupting Russian attempts to encircle Ukraine's 'fortress belt' — and a factor that may make Russian losses harder to verify in future operations.
What happened
The Institute for the Study of War reported that from March through September 2026 Russian forces lost net control of nearly 300 square kilometers of territory. In September, Russian troops captured 175.54 square kilometers but lost 256.35 square kilometers, a net loss of 80.81 square kilometers — an average of minus 2.69 square kilometers per day. Russian personnel losses in September exceeded 46,000 killed and wounded, the highest monthly figure for Russia in 2026. ISW's September 16 report found that Ukraine's 'Vivaldi' counter-offensive near Lyman in Donetsk Oblast achieved an operationally significant goal by disrupting Russian attempts to encircle the Ukrainian 'fortress belt.' The operation was first publicly confirmed on September 15 by Third Army Corps commander Andriy Biletsky, who said on September 28 that 176 square kilometers had been liberated as part of Vivaldi. Russian territorial gains slowed significantly from March 2026 onward and have remained low or negative since. ISW also noted that effective Ukrainian use of operations like this is likely to complicate obtaining a full picture of Russian losses going forward.
How Ukrainian sources describe it
The two Ukrainian outlets in the input frame September 2026 as a record-costly, failed month for Russia, foregrounding ISW's finding of negative net Russian gains and tying the territorial losses directly to Ukrainian operational successes. Coverage highlights two named Ukrainian operations: the earlier Airborne Assault Troops offensive on the Oleksandrivsk axis (January 29 to August 2026), which returned 745 square kilometers and 26 villages across Dnipropetrovsk, Donetsk, and Zaporizhzhia oblasts, and the 'Vivaldi' counter-offensive near Lyman. Ukrainian-source emphasis is on official Ukrainian statements — from President Zelensky, Commander Biletsky, and military-political observer Oleksandr Kovalenko — quantifying liberated territory and stressing the human cost inflicted on Russian forces.
Where reporting differs
The Russian Ministry of Defense claims control over the settlements of Ridkodub, Yampil, Novomykhailivka, and Nove, north of Lyman in Donetsk Oblast. There is no objective control data to confirm these Russian claims.
Background
The 'Vivaldi' operation in northern Donetsk Oblast had been underway for several months before details became available; Third Army Corps commander Andriy Biletsky first publicly confirmed it on September 15, and by September 28 said the Defense Forces had liberated 176 square kilometers as part of it. An earlier Airborne Assault Troops offensive on the Oleksandrivsk axis ran from January 29 to August 2026 and liberated 745 square kilometers, returning 26 villages in Dnipropetrovsk, Donetsk, and Zaporizhzhia oblasts. On September 30, military-political observer Oleksandr Kovalenko said the Defense Forces had liberated around 1,000 square kilometers in 2026; President Zelensky on May 22 cited 590 square kilometers freed since the start of the year, and told The Wall Street Journal on September 23 that Russians had captured about 890 square kilometers while the Defense Forces had de-occupied about 800 square kilometers. ISW also notes that Russia's existing force-generation system continues to recruit fewer soldiers than needed to replenish losses.